Diaphragm valve with mechanical pressure relief

ABSTRACT

A flush valve for a waste water system includes a valve body and a vent system. The valve includes a fluid inlet, a fluid outlet and a main valve element extending therebetween and adapted for movement to allow fluid flow therethrough based on a pressure differential across a portion of the main valve element. The vent system includes a control chamber, in flow communication with the fluid inlet of the valve and a vent outlet in flow communication with the fluid outlet of the valve. The flush valve further includes a relief system including a relief chamber with a relief inlet in flow communication with the control chamber and a relief outlet in flow communication with the vent outlet. A mechanical relief device is configured to open and close the relief inlet based on a predetermined fluid pressure at the relief inlet, thereby venting fluid from the control chamber to the vent outlet. The flush valve may further include a solenoid having a piston configured to open to establish flow communication between the control chamber and the vent outlet to effect opening of the main valve element, and to close to prevent fluid communication between the control chamber and the vent outlet to close the main valve element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of U.S. Provisional ApplicationSer. No. 60/617,264, filed Oct. 8, 2004, herein incorporated byreference in its entirety.

This application is related to U.S. application Ser. No. 11/246,457entitled “Method For Modifying A Plastic Body Valve For Use In A WasteWater System” and U.S. application Ser. No. 11/246,332 entitled“Diaphragm Valve With Electronic Pressure Detection”, both filedconcurrently herewith, and both herein incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to valves and, in one particularembodiment, to a plastic body valve having a pressure relief for use asa flush valve in a waste water system.

2. Technical Considerations

In most waste water systems, such as the flushing systems for urinals,commodes, and the like, the valves associated with these systems aretraditionally metal valves. Metal valves provide strength forwithstanding high-pressure fluctuations that may occur in the waterpressure of the flushing system and also maintain their ability tofunction over prolonged and consistent use. However, these traditionalmetal flush valves do have some drawbacks. For example, these metalvalves are typically relatively heavy and cumbersome to install andrepair. Moreover, with continued use, metal valves may corrode or rust,and/or develop mineral deposits, which can require replacement of theentire valve. Additionally, such metal valves are typically expensive tomanufacture and maintain.

Plastic valves are generally lighter in weight and less costly thanmetal valves and eliminate the corrosion associated with metal valveswhile reducing the development of mineral deposits. However, plasticvalves are typically not as strong as metal valves. That is, plasticvalves cannot typically withstand as high fluid pressures as metalvalves without leaking or breaking. While plastic valves do exist, theseknown plastic valves may not necessarily be capable of meeting theAmerican Society Of Sanitary Engineering (ASSE) requirements for use inconventional waste water systems. For example, one ASSE requirement isthat the valves in the waste water system must not leak at a fluidpressure of 500 psi or, if the valve incorporates a relief valve, thevalve must hold two-times the relief pressure without leaking.Conventional plastic bodied valves typically do not meet theselimitations.

Additionally, many modern commodes and/or urinals are designed tooperate most efficiently using a standard amount of water per flush,typically in the range of 1.5 to 2 gallons per flush. Therefore, knownmetal flush valves are designed to provide a selected amount of waterper flush when new. However, with continued or prolonged use over timeor as the internal components of the metal valve wear, it is notuncommon for these known metal flush valves to provide a differentamount of water per flush than they were originally designed to provide.For example, a metal flush valve originally designed to provide 1.6gallons per flush when new may eventually provide 2 or more gallons perflush due to valve component wear or use. For large applications, suchas hospitals, prisons, apartment buildings, and the like, this can leadto an increase in water usage and cost. Additionally, these known flushvalves cannot compensate for variations in water pressure during theflushing cycle that can also affect the amount of water per flush thevalve provides.

Therefore, it would be advantageous to provide a flush valve thatreduces or eliminates at least some of the problems associated withknown flush valves. For example, it would be advantageous to provide aplastic body flush valve with a relief system that meets current ASSErequirement. It would likewise be advantageous to provide a flush valvethat can provide a predetermined amount of water per flush despite valvewear and/or water pressure fluctuations.

SUMMARY OF THE INVENTION

A flush valve for a waste water system comprises a valve body and a ventsystem. The valve includes a fluid inlet, a fluid outlet and a mainvalve element extending between the fluid inlet and the fluid outlet.The main valve element is adapted for movement to allow fluid flowbetween the fluid inlet and the fluid outlet based on a pressuredifferential across a portion of the main valve element. The vent systemincludes a control chamber in flow communication with the fluid inlet ofthe valve and a vent outlet in flow communication with the fluid outletof the valve. The valve further includes a solenoid having a pistonconfigured to move between a first position opening the vent outlet anda closed position closing the vent outlet. Opening of the vent outletestablishes flow communication between the control chamber and the ventoutlet, thereby venting fluid from the control chamber to the fluidoutlet and establishing a pressure differential across a portion of themain valve element and permitting the main valve element to open forfluid flow between the fluid inlet and fluid outlet of the valve.Closing the vent outlet prevents fluid communication between the controlchamber and the vent outlet to close the main valve element. The valvefurther includes a relief system comprising a relief chamber having arelief inlet in flow communication with the control chamber, a reliefoutlet in flow communication with the vent outlet, and a mechanicalrelief device. The relief device, such a ball check valve, is configuredto open and close the relief inlet based on a predetermined fluidpressure at the relief inlet, thereby venting fluid from the controlchamber to the vent outlet.

In one embodiment, the relief inlet of the relief system is in directflow communication with the control chamber. In a further embodiment,the vent system further comprises a vent chamber in flow communicationwith the control chamber through a vent inlet passage extending betweenthe control chamber and the vent chamber, with the vent outlet in flowcommunication with the vent chamber. In such an embodiment, the reliefinlet may be in flow communication with the control chamber through thevent chamber. Alternatively, the relief inlet may be in flowcommunication with the control chamber through the vent inlet passage.Moreover, the mechanical relief device in one particular embodiment maycomprise a ball relief valve having a ball biased by a spring toward aclosed position of the relief inlet. The spring bias is adapted to beovercome based on the fluid pressure at the relief inlet exceeding thepredetermined fluid pressure at the relief inlet.

In a further embodiment, an improved diaphragm flush valve is provided.The valve comprises a plastic valve body including a fluid inlet and afluid outlet and a main valve element adapted for movement to allowfluid flow between the fluid inlet and the fluid outlet based on apressure differential across a portion of the main valve element, aswell as a vent system for venting fluid from the fluid inlet to thefluid outlet to establish a pressure differential across a portion ofthe main valve element to open the main valve element. The improvedvalve further includes a pressure relief system within the valve amechanical relief valve in flow communication with the fluid inlet ofthe valve. The relief valve is configured to open based on the fluidpressure at the relief valve exceeding a predetermined fluid pressurebeyond that required to maintain the main valve element closed, therebycausing fluid to vent from the fluid inlet to the fluid outlet andrelieving the pressure within the valve.

In one embodiment, the pressure relief assembly may be associated withthe main valve element, such as swing check valve having a pressurerelief valve built therein. In such an embodiment, the relief valve isconfigured to open based on the fluid pressure at the relief valveexceeding a predetermined fluid pressure to cause fluid to vent from thefluid inlet to the fluid outlet and relieving the pressure within thevalve without causing opening of the main valve element.

A diaphragm flush valve for a waste water system may further comprise aplastic valve body having a diaphragm, a plastic cover connectable tothe valve body, and a vent system defining a control chamber, a ventchamber, a vent inlet extending between the control chamber and the ventchamber, and a vent outlet in flow communication with the vent chamber.The diaphragm flush valve also comprises a relief chamber having arelief inlet in flow communication with at least one of the controlchamber, the vent chamber, or the vent inlet. The relief chamber alsoincludes a relief outlet in flow communication with the vent outlet. Thediaphragm flush valve further comprises a solenoid having a pistonconfigured to open and close the vent outlet. A mechanical relief deviceis configured to open and close the relief inlet. In one non-limitingembodiment, the relief device comprises a ball relief valve.

A flush valve for a waste water system comprises a valve body having aninlet, an outlet, and a flow passage extending between the inlet and theoutlet. The flush valve also includes a valve element configured to openand close the flow passage, and a mechanical relief assembly operativelyassociated with the valve element.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional advantages and details of the invention are explained ingreater detail below with reference to the exemplary embodiments thatare illustrated in the accompanying schematic figures, in which:

FIG. 1 is a side view of a plastic bodied valve incorporating featuresof the invention;

FIG. 2 is a top view of the valve of FIG. 1;

FIG. 3 is an exploded view of the valve of FIG. 1;

FIG. 4 is a side, sectional view of the valve of FIG. 1 in a closedconfiguration;

FIG. 5 is a side, sectional view of the valve of FIG. 1 in an openconfiguration;

FIG. 6 is a side, cut-away view of a portion of a valve incorporating avalve relief system of the invention;

FIGS. 7-9 are side, cut-away views of valve portions similar to FIG. 3but incorporating alternative valve relief systems;

FIG. 10 is a side, sectional view of a valve of the invention having avalve relief system located in the valve body;

FIG. 11 is a side, cut-away view (not to scale) of an alternative valverelief system of the invention;

FIG. 12 is a side, cut-away view (not to scale) of another valve systemincorporating features of the invention; and

FIG. 13 is a side, cut-away view (not to scale) of a further valvesystem of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, spatial or directional terms, such as “up”, “down”,“above”, “below”, “top”, “bottom”, and the like, relate to the inventionas it is shown in the drawing figures. However, it is to be understoodthat the invention can assume various alternative orientations and,accordingly, such terms are not to be considered as limiting. Further,all numbers expressing dimensions, physical characteristics, processingparameters, quantities of ingredients, reaction conditions, and thelike, used in the specification and claims are to be understood as beingmodified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical values set forth in thefollowing specification and claims are approximations that can varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical value should at least be construed in light of the numberof reported significant digits and by applying ordinary roundingtechniques. Moreover, all ranges disclosed herein are to be understoodto encompass any and all subranges subsumed therein. For example, astated range of “1 to 10” should be considered to include any and allsubranges between (and inclusive of) the minimum value of 1 and themaximum value of 10; that is, all subranges beginning with a minimumvalue of 1 or more and ending with a maximum value of 10 or less, e.g.,1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc. All references referred to herein,such as but not limited to issued patents and published applications,are to be understood to be incorporated by reference in their entirety.The term “mechanical relief” refers to a relief device or system thatdoes not require electricity or electrical power to function in apressure relieving capacity. The term “electronic relief” refers to arelief device or system that utilizes electricity or electrical power tofunction in a pressure relieving capacity.

FIGS. 1-5 show a valve 10 of the present invention. The basic componentsof the valve 10 will first be described in order to clarify thesubsequent discussion of the invention.

In one non-limiting embodiment, the valve 10 can be a diaphragm-typevalve having a valve housing 12 formed by a valve body 14 and a cover16. The valve body 14 and/or cover 16 can be of any desired material,for example, metal or plastic. In one non-limiting embodiment, the valvebody 14 and cover 16 can both be made of plastic or one can be plasticand the other metal. The valve body 14 has a flow passage extendingtherethrough with an inlet end 18 and an outlet end 20.

The cover 16 is connected to the valve body 14 by a plurality of bolts22, such as aluminum or stainless steel bolts, threadably engagable withinsert nuts in the valve body 14. The insert nuts can also be metal,such as brass or, more preferably, steel. A diaphragm 26 of suitablematerial, such as rubber or plastic, is sandwiched between the valvebody 14 and the cover 16 to form a seal between the two chambers of thevalve 10. A valve element 300 is positioned in the flow passage and theupper side of the valve element 300 engages the central region of thediaphragm 26 when the valve 10 is assembled. In one embodiment, thevalve element 300 is a conventional swing check valve. The valve 10further includes a solenoid 28 threadably attached to the cover 16 andoperationally connected with a vent system to control water pressure ina control chamber formed above the diaphragm 26, as is typical in knowndiaphragm valves. As will be described in more detail below, in onenon-limiting embodiment the vent system includes a passage, such as acrescent-shaped vent passage, in flow communication on one end with thecontrol chamber and on the other end with a vent chamber. Flow through avent outlet for the vent chamber is controlled by a plunger 29associated with the solenoid 28, which can be moved to open or close thevent outlet. The valve 10 also includes a rotatable stop 30 that can beused to adjust or control the maximum opening position of the valveelement.

The valve 10 also includes a swing check retaining ring 302 to retainthe valve element 300 in the valve body 14. In the illustratedembodiment, the solenoid 28 is connected to the valve cover 16 by ableed plug or fitting 90. A manual override lever 304 can be operativelyconnected to the solenoid 28.

FIG. 4 shows the valve 10 in a closed configuration in which the valveelement 300 blocks the flow passage, preventing fluid flow through thevalve 10. FIG. 5 shows the valve 10 in an open configuration in whichfluid can flow from the inlet end 18, through the flow passage, and outthe outlet end 20.

The above-described diaphragm valve basic components and their operationwill be well understood by one of ordinary skill in the diaphragm valveart and, hence, will not be described in any great detail. Examples ofknown diaphragm valves and their operation are described, for example,in U.S. Pat. Nos. 4,336,918; 4,301,992; 4,893,645; 4,797,820; 4,477,051;4,787,413; 5,853,026; and 6,557,580. However, unlike conventionaldiaphragm valves, the valve 10 of the invention includes operationalelements and/or a relief system in accordance with the invention, aswill now be described, which make the valve particularly useful as aflush valve in a waste water system.

A portion of the valve 10 of the invention incorporating a mechanicalrelief assembly is shown in FIG. 6. The bleed plug or fitting 90 has afirst end 92 and a second end 94. The first end 92 is connectable withthe valve 10, such as with the cover 16, and the second end 94 engagesthe solenoid 28. In the embodiment illustrated in FIG. 6, the first end92 of the fitting 90 has external threads 96 configured to engagethreads on the cover 16, and the second end 94 has internal threads 98configured to engage threads on the solenoid 28. The valve 10 has a ventsystem incorporating a vent inlet passage 100 with one end (lower end)in flow communication with a control chamber 102 and the other end(upper end) in flow communication with a vent chamber 104. A vent valveseat 106 is located in the vent chamber 104 and is in flow communicationwith a vent outlet conduit 108. When the fitting 90 is engaged with thecover 16, the first end 92 of the fitting 90 contacts a raised sealingmember 107. An outlet conduit 109 in the sealing member 107 aligns withthe lower end of the outlet conduit 108 in the fitting 90.

Flow through the outlet conduit 108 is controlled by a piston 110 of thesolenoid 28. The piston 110 is slidable within a core tube 111surrounded by a coil 113, as is conventional in many solenoids. As shownin FIG. 6, when the piston 110 is engaged with the vent valve seat 106,flow to the vent outlet conduit 108 is prevented. The fluid pressure inthe control chamber 102 is built up to be equal to the fluid pressure ofthe fluid supply source entering valve 10 through inlet end 18. Inparticular, fluid flows into valve 10 through inlet end 18, throughchamber inlet 15 and into control chamber 102 above diaphragm 26.Control chamber 102 extends across the top of valve 10 over diaphragm 26and into the portion of valve 10 to which solenoid 28 is threadedthereto. With the piston 110 of solenoid 28 seated on vent valve seat106, vent chamber 104 is closed from fluid communication across ventvalve seat 106, and control chamber 102 is therefore closed as well. Thefluid pressure within control chamber 102 applies a force acrossdiaphragm 26, maintaining the diaphragm 26 in an extending position andpreventing it from lifting, thereby maintaining the swing check valve300 in a downward state and preventing swing check valve 300 fromlifting, thus preventing fluid flow through the valve 10. When thepiston 110 is retracted (i.e., moved upwardly), such as by energizingthe coil 113, fluid communication is established between vent chamber104 and vent outlet 108, thus opening the vent outlet conduit 108 andallowing fluid flow from the vent inlet passage 100, through the ventchamber 104, and out the vent outlet conduit 108 into the outlet end 20of the valve 10, from where the fluid passes to the fixture associatedwith valve 10. The vent system is used to bleed pressure from thecontrol chamber 102 to open the main valve element in the valve body 14.This allows the valve element to be opened and closed to control fluidflow through the valve 10.

More particularly, as will be appreciated by one of ordinary skill inthe art, the solenoid 28 is connected to a conventional actuator, suchas a conventional push-button actuator, to effect actuation of the valve10 during normal use of the valve 10, such as to effect flushing of anattached fixture. To flush the equipment associated with the valve 10,the actuator is activated. This sends an electrical signal to the coil113 which energizes the coil 113, thereby causing the piston 110 to liftfrom the vent valve seat 106. Such movement opens vent valve seat 106and places vent chamber 104 in fluid communication with vent outlet 108.Thus, fluid flow is established from the control chamber 102, throughthe vent inlet 100, through vent chamber 104, and out the vent outlet108, into the outlet end 20 of the valve 10. This relieves the pressurein the control chamber 102, creating a pressure differential across thediaphragm 26 and the main valve element, i.e. the swing check valve 300,in the flow passage, which is pressurized with fluid pressure from fluidflowing from the main water source attached at inlet end 18 of valve 10.This pressure differential effects movement of the swing check valve300, thereby opening valve 10 for fluid flow between inlet end 18 andoutlet end 20. To close the main valve element, the solenoid 28 isdisengaged (e.g., the coil 113 is de-energized) such that the piston 110re-engages the vent valve seat 106 to close the vent outlet 108. Suchclosure closes off any fluid flow therethrough, thereby allowing fluid,i.e. water, to re-accumulate in vent chamber 104, and re-pressurizingthe control chamber 102 above diaphragm 26 and closing swing check valve300.

Valve 10 of the present invention further incorporates a pressure reliefsystem or assembly in order to prevent the build-up of internal pressurewithin valve 10 beyond a pre-determined threshold limit. In particular,valve 10 is designed for use as a flow control valve in water systems,such as a waste water system. Such water systems involve incoming waterflow from a main water system, which may be a city water supply. Assuch, these water systems are subject to fluctuations in water pressure.In order to prevent damage to the internal operations of the valve fromany spikes in water pressure or excessive build up of pressure, valve 10incorporates a pressure relief system.

The pressure relief system may be incorporated into any portion of thevalve 10. In one embodiment, the relief system is incorporated adjacentthe solenoid operation of the valve 10. In particular, in one practiceof the invention, the valve 10 can incorporate a mechanical reliefassembly 112 at fitting 90, as depicted in FIG. 6. In this embodiment, arelief system comprises a relief chamber 114 formed in the fitting 90.This can be done in any conventional manner, such as by drilling ormolding a fitting to have the relief chamber 114. The relief chamber 114includes a relief inlet 116 in flow communication with the controlchamber 102 and a relief outlet 118 in flow communication with the ventoutlet conduit 108. A mechanical relief device, such as a relief valve120, is positioned in the relief chamber 114. The relief valve 120 canbe of any conventional type. However, in the illustrated embodiment, therelief valve 120 is a ball relief valve having a ball 122 biased by aspring 124. The spring 124 can be connected at an end opposite of theball to a plug 126 that can be formed in the fitting 90 or can beengaged with the fitting 90 in any conventional manner. For example, theplug 126 can be configured to engage threads formed in the reliefchamber 114. Alternatively, the upper end of the relief chamber 114 canbe closed, in which case no plug 126 would be required.

The spring 124 is configured such that at fluid pressures below apredefined value, the spring bias pushes the ball 122 against a sealingsurface at the relief inlet 116 opening to close the relief inlet 116.However, if the forces applied against the ball 122 based on the fluidpressure applied against the ball 122 at the relief inlet 116 reaches orexceeds the predefined value (based on the bias of the spring 124), thefluid pressure overcomes the bias of the spring 124 to push the ball 122inwardly to open the relief inlet 116 to prevent fluid flow through therelief assembly 112. As will be appreciated by one skilled in the art,the predefined relief pressure can be changed or adjusted by replacingthe spring 124 with another spring of differing spring bias.

In the practice of the invention, the relief assembly 112 prevents overpressurization of the interior of the valve 10 to prevent leakage and/ordamage to the valve at high pressures. For example, with reference toFIG. 6, should the pressure in the control chamber 102 meet or exceed apredetermined relief pressure based on the bias of the spring 124, theball 122 is pushed away from the inlet 116 against the bias of thespring 124 to allow fluid to flow through the inlet 116 and out therelief outlet 118 into the vent outlet 108. When the fluid pressuredrops below the preset value for the relief valve 120, the bias of thespring 124 forces the ball 122 to close the inlet 116 to stop anyadditional fluid flow through the relief assembly 112.

FIG. 7 shows an alternative configuration of a mechanical reliefassembly 128 of the invention. In this embodiment, the inlet 116 of therelief chamber 114 is in flow communication with the water source fromthe control chamber 102 at the vent chamber 104 rather than directly atthe control chamber 102. However, the relief assembly 128 would work ina similar manner as the relief assembly 112 described above in that whenthe pressure in the vent chamber 104 rises above a pre-selected value,the fluid pressure forces the ball 122 downwardly against the bias ofthe spring to allow fluid to flow out of the relief outlet 118 and intothe vent outlet 108, thereby relieving the pressure against thediaphragm 26 to effect movement of the swing check valve 300, therebyopening valve 10 for fluid flow therethrough and relieving the pressureinside valve 10 to protect from damage or leakage.

FIG. 8 is an alternative embodiment of a mechanical relief assembly 130incorporating features of the invention. In this embodiment, the inlet116 for the relief chamber 114 is in flow communication with the ventinlet passage 100 such that when pressure in the vent inlet passage 100rises above the pre-selected level, the relief valve 120 opens and fluidflows from the vent inlet passage 100 through the relief outlet 118 intothe vent outlet 108.

FIG. 9 is similar to the configuration shown in FIG. 7 but thespring-biased ball relief is replaced with a compressible plug or member150 configured to deform at a pre-selected pressure such that when thepressure in the vent chamber 104 reaches the pre-selected pressure, thepressure deforms the compressible member 150 to open the relief outlet118. In one specific embodiment, the compressible member 150 can be of adurometer selected to provide a selected opening pressure. The materialcan be, for example, neoprene, rubber, or the like.

A further mechanical relief assembly 310 is shown in FIG. 10. In thisembodiment, the relief assembly 310 is formed in a portion of the valvebody 14, such as in the valve element 300, rather than in the solenoid28 as in the embodiments described above. The relief assembly 310comprises a relief chamber 312 formed in the valve element 300 andhaving a relief inlet 314 on the inlet side 316 of the valve element300, i.e., in flow communication with the inlet side of the flowpassage. A relief outlet 318 extends between the relief chamber 312 andan outlet side 320 of the valve element 300, i.e., one end of the reliefoutlet 318 is in flow communication with the relief chamber 312 and theother end of the relief outlet 318 is in flow communication with theoutlet side of the flow passage.

A mechanical relief valve 322 (relief device) of any conventional typeis located in the relief chamber 312. In the illustrated embodiment, themechanical relief valve 322 is depicted as a ball relief valve having aball 122 biased by a spring 124 as described above. The spring 124 isselected or configured such that at fluid pressures on the inlet side316 of the valve element 300 below a predetermined value, the spring 124pushes the ball 122 against a sealing surface at the relief inlet 314 toclose the relief inlet 314. However, if the fluid pressure on the inletside 316 of the valve element 300 reaches or exceeds the predeterminedvalue based on the bias of the spring 124, the fluid pressure overcomesthe bias of the spring 124 to push the ball 122 inwardly to open therelief inlet 314 and allow fluid flow through the relief chamber 312 andout the relief outlet 318. In this manner, the inlet side of the flowpassage is placed in flow communication with the outlet side of the flowpassage through the valve element 300 via the relief assembly 310,thereby venting a portion of fluid, i.e., water, therethrough. Oncesufficient fluid flow through the relief assembly 310 causes the fluidpressure at the inlet side 316 of the valve to be reduced to a valuebelow the predetermined threshold based on the bias of the spring 124,the spring 124 pushes the ball 122 back to the sealing position, closingoff the relief chamber 312 from further fluid flow therethrough. Thisembodiment prevents over-pressurization of the valve 10 based onbleeding small volumes of water through the valve 10, therebyeffectively relieving internal pressure build-up without effecting fullopening of the valve element 300, and therefore without fully flushingany fixture associated with the valve 10.

In a further embodiment of the invention, the pressure relief systemincorporates an electronic mechanism for detecting pressure within thevalve in excess of a predetermined limit, as opposed to (or in additionto) a mechanical mechanism as set forth in the embodiments previouslydescribed. In particular, an electronic pressure relief assembly may beincorporated into a portion of valve 10, so as to effectively measure towater pressure within valve 10, such as within control chamber 102, toprevent a build up of excessive pressure therein. Desirably, such anelectronic pressure relief system may be incorporated into a portion ofthe valve adjacent other electronically operated features of the valve,such as adjacent to or integrated with the solenoid portion of thevalve. In this manner, a conventional valve such as that disclosed inFIG. 1 above or such as disclosed U.S. Pat. No. 4,336,918 can be easilymodified and retrofitted by replacing a conventional solenoid operatorwith a modified solenoid incorporating an electronic relief assembly asdisclosed in the present invention.

For example, a portion of a valve 10 incorporating an electronic reliefassembly 200 in accordance with a further embodiment is shown in FIG.11. In this embodiment, a modified solenoid 202 is utilized. Thesolenoid 202 engages the plug or fitting 90, for example, as describedabove with respect to FIG. 6. The solenoid 202 includes a piston 204slidable within a core tube 206. A coil surrounds at least a portion ofthe core tube 206. The coil can be a single coil 113 as described aboveor, in the illustrated embodiment, the coil can comprise a first coilsection 208 and a second coil section 210. The first coil section 208 islocated at or near the bottom or open end 212 of the core tube 206. Thesecond coil section 210 is located at or near the top or closed end 214of the core tube 206.

In this electronic relief assembly 200, a pressure transducer 216 isconnected to the solenoid 202 and is configured to measure the fluidpressure within the valve, e.g., in the vent chamber 104, which is influid communication with the control chamber 102. For example, in oneembodiment the pressure transducer 216 can be configured to extend intothe vent chamber 104. Alternatively, in the embodiment shown in FIG. 11,the pressure transducer 216 can be connected to the top 214 of the coretube 206 and can extend into the interior of the core tube 206. As willbe appreciated by one skilled in the art, a gap exists between theoutside diameter of the piston 204 and the inside diameter of the coretube 206 such that fluid in the vent chamber 104 flows into the coretube 206 around the piston 204. Thus, the pressure in the core tube 206should be substantially the same as that in the vent chamber 104 and thecontrol chamber 102. The pressure transducer 216 is in electroniccommunication with a control board 218 in any conventional manner, suchas by one or more wires or cables 220. The control board 218 can be, forexample, a conventional 4IO or 8IO control board, as is known to thoseof ordinary skill in the art. The control board 218 is connected to anelectrical power source to provide electrical power to the solenoid 202in any conventional manner, such as by one or more cables 222. Thecontrol board 218 is in electronic communication, such as by a wire orcable 224, with an actuator 226, such as a conventional push button orsimilar actuator.

The relief assembly 200 in the embodiment of FIG. 11 operates as followsin one non-limiting embodiment. The pressure transducer 216 senses thestatic fluid pressure inside the core tube 206. By “static pressure” ismeant the fluid pressure when the solenoid 202 is de-energized, that is,when the piston 204 engages the valve seat 106. The system can beconfigured such that a pressure range sensed by the pressure transducer216 can correspond to an output signal of the transducer 216. Forexample, a pressure range of 0 to 150 psi can correspond to an outputsignal of 0 to 5 volts DC. A high-voltage threshold can bepredetermined, which corresponds to a relief pressure for the reliefassembly 200. By “relief pressure” is meant the fluid pressure at whichthe relief assembly 200 is activated. The static pressure can bemonitored either continuously or intermittently by a microprocessor 228associated with a pressure transducer control 230 on the control board218. Depending upon the output signal of the pressure transducer 216, anamplifier 232 can also be present on the control board 218 to boost theoutput signal from the pressure transducer 216, if needed. In any event,when the high-voltage threshold is detected (i.e., the relief pressureis attained), the microprocessor 228 sends a signal to energize thesolenoid 202.

In one embodiment, the solenoid can be energized for a predeterminedperiod of time, for example, in the range of 1 to 3 seconds. This liftsthe piston 204 off of the valve seat 106 for that predetermined periodof time to open the vent outlet 108 for fluid flow therethrough, therebyreleasing a portion of the fluid within vent chamber 104 and controlchamber 102, and lowering the pressure within the vent chamber 104 andcontrol chamber 102. After this predetermined period of time, thesolenoid 202 is de-energized such that the piston 204 again engages thevalve seat 106. The pressure transducer 216 may thereafter again sensesthe static pressure inside the core tube 206. If the static pressure asmeasured within vent chamber 104 is still above the relief pressure(that is, the output signal of the pressure transducer 216 is at orabove the high-voltage threshold), the microprocessor 228 againactivates the solenoid 202 for a predetermined period of time to liftthe piston 204 to again open the vent outlet 108 for fluid flowtherethrough, relieving at least some of the fluid pressure within thevent chamber 104 and control chamber 102. This cycle can continue untilthe static pressure sensed by the pressure transducer 216 is below thepredetermined relief pressure.

In a further embodiment, operation of the solenoid to relieve thepressure within valve 10 is not necessarily based on a predeterminedtime value for venting a specified volume of fluid out of vent chamber104 and control chamber 102, but is instead based on the internalpressure within valve 10 during the venting as measured by the pressuretransducer 216. For example, when the high-voltage threshold is attained(i.e. the relief pressure is attained based on the measurement from thepressure transducer 216), the solenoid 202 is activated to lift thepiston 204 and relieve the pressure, and the solenoid 202 remainsenergized. In this embodiment, the pressure transducer 216 continues tomonitor the internal fluid pressure within the core tube 111 and/or thevent chamber 104 while the solenoid 202 is energized. The solenoid 202remains energized until the pressure transducer 216 senses a closingvoltage threshold, i.e., a voltage associated with a predefined fluidpressure at which the solenoid 202 is to be de-energized. The closingvoltage threshold corresponds to a voltage output corresponding to adynamic fluid pressure defined as the closing pressure. By “dynamicfluid pressure” is meant the fluid pressure in the core tube 111 and/orvent chamber 104 while the solenoid 202 is energized, that is while thepiston 204 is off of the valve seat 106 and fluid is flowing through thevent chamber 104 and out the vent outlet 108. For example, themicroprocessor 228 may be programmed such that a closing voltagethreshold may correspond to a specific pressure within the vent chamber104, such as a voltage threshold of 3.2V DC corresponding to 100 psi,representing an acceptable internal pressure to prevent damage withinvalve 10. When the dynamic fluid pressure measured by pressuretransducer 216 reaches the acceptable threshold corresponding to theclosing voltage threshold, the microprocessor 228 de-energizes thesolenoid 202 to cause the piston 204 to move downwardly to re-engage thevalve seat 106 and seal off the vent outlet 108.

As will be appreciated by one skilled in the art, the above reliefmethods may allow sufficient fluid flow through out of vent chamber 104and control chamber 102 through vent outlet 108 to cause a sufficientdrop in pressure within control chamber 102 which would releasediaphragm 26, thereby opening the main valve element 300 of valve 10. Assuch, the equipment or fixture associated with the flush valve 10, suchas a commode or urinal, would be caused to flush when the piston 204 islifted from the valve seat 106 to relieve the fluid pressure. Theinvention, however, further provides embodiments which effectivelyrelease the pressure within valve 10 without necessarily dropping thepressure of control chamber 102 below the required threshold to maintaindiaphragm 26 closed, thereby preventing operation of valve 10.

For example, it is contemplated that in a single coil system such asthat described above, the microprocessor may be programmed differentlydepending on whether a normal flush request from actuator 226 isreceived or whether a high voltage threshold is detected based on asignal from the pressure measured by the pressure transducer 216. If theequipment is to be flushed such as based on receipt of a normal flushrequest from actuator 226, the microprocessor 228 sends a signal toenergize the solenoid to lift the piston 204 off of the valve seat 106to open the vent outlet 108 for venting of control chamber 102 for asufficient period of time typically associated with operation of thevalve 10, in order to effect opening of the valve element of the valve10 and to flush the associated fixture or equipment, such as for aperiod of more than 3 seconds. On the other hand, when a high voltagethreshold is detected based readings from the pressure transducer 216,the microprocessor 228 can send a signal to energize the solenoid foronly a limited predetermined period of time below that which is normallyassociated with release of the control chamber 102 which would effectopening of the valve 10, such as a period of less than 1 second. In thismanner, the pressure can be effectively released within valve 10 withouteffecting a full flush of the fixture associated with the valve 10.

Alternatively, the illustrated embodiment of FIG. 11 utilizes a two-partcoil to prevent complete opening of valve 10 to prevent flushing of theassociated equipment. For example, if the equipment is to be flushedsuch as based on receipt of a normal flush request from actuator 226,the upper or second coil section 210 can be energized to lift the piston204 off of the valve seat 106 to open the vent outlet 108 for asufficient period of time typically associated with venting of controlchamber 102 for operation of the valve 10, in order to effect opening ofthe valve element of the valve 10 and to flush the associated fixture orequipment. However, if a pressure above the high-voltage threshold isdetected by the pressure transducer 216, the microprocessor 228activates only the lower coil 208 to slightly lift the piston 204 off ofthe valve seat 106 for a brief period of time, e.g., less than 1 second.If the piston 204 is lifted only for a short period of time and/or islifted only slightly off of the valve seat 106 in order to lower thepressure in the vent chamber 104, flushing of the associated equipmentmay be prevented.

Under normal operation, when the valve 10 is to be opened to permitflushing of an associated component, the actuator 226 is actuated, suchas by pressing a button. Upon receiving the actuation signal, thecontrol board 218 sends a signal via the cable 222 to the solenoid 202to energize the coils (113 or 210) to lift the piston 204 off of thevalve seat 106. This vents the fluid in the vent chamber 104 through thevent outlet 108, thereby venting the control chamber 102 and opening thevalve element 300 of the valve 10. In one practice of the invention,when the actuation signal is received, the microprocessor 228 determinesthe static fluid pressure inside the core tube 206 by the pressuretransducer 216. Based on this sensed static pressure, the microprocessor228 calculates a flush time in order for the valve 10 to deliver adesired quantity of water. The microprocessor 228 actuates the solenoid202 to lift the piston 204 for a predetermined specific period of timesuch that the valve 10 provides a predetermined quantity of fluid. Forexample, if a total volume of fluid flow through the valve 10 is desiredto be 1.6 gallons and the sensed static pressure is 60 psi, themicroprocessor 228 can actuate the solenoid 202 for a firstpredetermined period of time corresponding to a flow through the valve10 of 1.6 gallons. However, if the sensed static pressure is 50 psi, themicroprocessor 228 would actuate the solenoid 202 for a secondpredetermined period of time greater than the first predetermined periodof time in order to provide the same amount of water through the valve10.

In another aspect of the invention, the pressure transducer 216 can beadapted to monitor the dynamic fluid pressure during operation of thevalve to control the amount of water flow through valve 10. For example,the precise volume of fluid flow through valve 10 for a given period oftime can be calculated based on the interior volume of valve 10, thetime of flow through valve 10 and the fluid pressure of the waterflowing through valve 10. For a given fluid pressure, it can becalculated that the operating time for valve 10 may be a certain periodof time for a given flow volume. For example, it may be known based onnormal line pressure from the water source through inlet 18 that valve10 should remain open for a specified period of time (based on operationof solenoid 202), such as 3 seconds, to effect a specified flow volume,such as 1.6 gallons per flush. The line pressure from the water source,however, may fluctuate depending on a number of factors, such asmultiple fixtures attached to the water source operating simultaneously.By monitoring the dynamic fluid pressure within the valve 10 duringoperation of the valve, such as through the pressure transducer 216, theoperating time of the valve can be adjusted during operation of thevalve 10 so as to ensure that the desired flow volume is achievedthrough the valve 10.

For example, when the actuation signal is received from the actuator226, the microprocessor 228 can send signal the pressure transducer 216to sense the static pressure of the fluid within valve 10, such as inthe core tube 206. Based upon this sensed static pressure, an initialactuation time for the solenoid 202 to provide a predetermined volume ofwater through the valve 10 is determined. This initial actuation timefor solenoid 202 can be pre-calculated based upon the sensed pressurewhen applied with the known interior volume of valve 10 and the desiredamount of water flow therethrough. In this embodiment, the pressuretransducer 216 continues to monitor the dynamic fluid pressure in thecore tube 206 during valve actuation and operation. If this dynamicfluid pressure varies during the flushing cycle, the microprocessor 228adjusts the actuation time of the solenoid 202 in order to compensatefor fluid pressure variation, to ensure that the desired volume offlushing water is delivered through valve 10.

For example, a desired flow volume, such as 1.6 gallons per flush, isrequired when a normal flush request is received. Based upon the initialstatic pressure measurement, the microprocessor calculates the initialoperating time for solenoid 202 to ensure that valve 10 remains open forthe calculated operating time. For example, if based upon the initialstatic pressure measurement a flush time of 3 seconds is determined bythe microprocessor 228 to correspond to a desired total volume throughthe valve 10, such as 1.6 gallons per flush, the solenoid 202 isactuated for the determined time period. However, if during thisflushing process the dynamic fluid pressure sensed by the pressuretransducer 216 varies from a predetermined value or range, such as byincreasing or decreasing from the initial static pressure beyond apredetermined amount, the microprocessor 228 recalculates the amount oftime the solenoid 202 needs to be activated in order to maintain valve10 open for an appropriate time to ensure that the desired volume flowtherethrough is achieved, such as a discharge volume of 1.6 gallons fromthe valve 10. This ensures a desired amount of fluid is discharged fromthe valve 10 even if the fluid pressure varies during the operation ofthe valve 10 such as during the flushing process. That is, knowing theinitial pressure, the dynamic pressure, and the flow rate through thevalve 10 at the dynamic pressure, the microprocessor 228 can determinean actual flush time needed to flush a desired amount of water throughthe valve 10. In this manner, the effective flushing volume of valve 10will remain constant over the life of valve 10, regardless of wearing ofthe internal components of valve 10, which can alter the effectiveflushing volume of conventional diaphragm valves over time.

In the embodiment shown in FIG. 12, the pressure transducer control 230is located on the valve 10, such as on the solenoid 202. The pressuretransducer control 230 is connected to the main control board 218 in anyconventional manner, such as by a cable 234 having one or more wires.The pressure transducer 216 is connected to the pressure transducercontrol board 230 in any conventional manner, such as by cables or wires236. The control board 218 can provide electrical power to thetransducer control board 230 and/or solenoid 202, such as by a cable237, such that the relief function and flush function as described abovecan be maintained.

In the embodiment, shown in FIG. 13, the main control board 218, whichincludes the pressure transducer control 230 and associatedmicroprocessor 228 and amplifier 232, is located directly on the valve10, such as on the solenoid 202. A power source 240, such as aconventional wall outlet or a battery, is in electronic communicationwith the main control board 218 and/or solenoid 202 in conventionalmanner, such as by a cable 242. The actuator 226 is connected to themain control board 218 on the solenoid 202. The flushing and/or reliefactions occur in similar manner as described above.

In the electronic relief systems described above, electrical power canbe continually provided to the pressure transducer 216 such that thetransducer 216 continually monitors the fluid pressure within the valve10. However, in an alternate embodiment, electrical power may besupplied to the pressure transducer 216 to effect monitoring at aspecific time only, such as when the actuator 226 is activated. When theactuator 226 is activated, the microprocessor 228 sends power to thetransducer 216 to sense the static fluid pressure. Based upon thisstatic pressure, a flush time (i.e., solenoid activation time) iscalculated to achieve a desired flush volume. The transducer 216 canremain powered during the flush to monitor the dynamic fluid pressureand adjust the flush time as described above. Moreover, themicroprocessor 228 may be programmed to supply power to the pressuretransducer 216 at intermittent time periods, such as every 10 minutes,to intermittently monitor the internal pressure within valve 10.

It is further contemplated that the pressure monitoring function of thetransducer 216 may be utilized as a maintenance function for valve 10.For example, the internal components of diaphragm valves typically wearover time, which can result in prolonged fluid flow therethrough,wasting water. Oftentimes, such wearing causes the valve to take alonger-period of time in order to reseal the diaphragm based upon thetime required to build up water pressure within the valve 10 at theinlet side of the diaphragm 26. The pressure transducer 216 may beprogrammed to detect the water pressure within valve 10 after a certainperiod of time after a normal flush as requested and effected. Thetypical range of time required to achieve the water pressure necessaryto effect resealing of diaphragm 26 and closure of the valve 10 is knownbased on normal operation of the valve 10. A comparison of the waterpressure after a normal flush at the known time period can provideinformation regarding the wear of the valve. For example, if the waterpressure detected after the predetermined time period is lower than thetypical water pressure value as known, valve 10 may require servicing orreplacement. A signal including this information could be transmitted toa central processing unit, which could then alert the maintenance staffthat servicing is required.

It will be readily appreciated by those skilled in the art thatmodifications may be made to the invention without departing from theconcepts disclosed in the foregoing description. For example, variouscomponents of the mechanical and electronic relief devices describedabove can be used together in the same valve. Accordingly, theparticular embodiments described in detail herein are illustrative onlyand are not limiting to the scope of the invention, which is to be giventhe full breadth of the appended claims and any and all equivalentsthereof.

What is claimed is:
 1. A flush valve for a waste water system,comprising: a valve comprising a fluid inlet, a fluid outlet and a mainvalve element extending between the fluid inlet and the fluid outlet,the main valve element adapted for movement to allow fluid flow betweenthe fluid inlet and the fluid outlet based on a pressure differentialacross a portion of the main valve element; a vent system comprising acontrol chamber in flow communication with the fluid inlet of the valve,a vent chamber in flow communication with the control chamber through avent inlet passage extending between the control chamber and the ventchamber, and a vent outlet passage extending between and in flowcommunication with the fluid outlet and the vent chamber; a solenoidhaving a piston configured to open to establish flow communicationbetween the control chamber and the vent outlet passage, thereby ventingfluid from the control chamber to the fluid outlet and establishing apressure differential across a portion of the main valve element andpermitting the main valve element to open for fluid flow between thefluid inlet and fluid outlet of the valve, and to close to prevent fluidcommunication between the control chamber and the vent outlet passage toclose the main valve element; a bleed fitting having a first endconnected to the valve and a second end connected to the solenoid suchthat the piston of the solenoid moves into and out of the bleed fitting;and a relief system incorporated into the bleed fitting comprising arelief chamber having a relief inlet in flow communication with thecontrol chamber, a relief outlet in flow communication with the ventoutlet passage, and a mechanical relief device positioned completelywithin the bleed fitting and configured to open and close the reliefinlet based on a predetermined fluid pressure at the relief inlet,thereby venting fluid from the control chamber to the vent outlet,wherein at least the vent outlet passage and the vent inlet passage ofthe vent system and the relief system are positioned within the bleedfitting and the vent outlet passage, the vent inlet passage, and therelief chamber are positioned parallel to each other and the reliefoutlet is positioned perpendicularly to the relief chamber and the ventoutlet passage.
 2. The flush valve according to claim 1, wherein atleast a portion of the body defining the valve is constructed of aplastic material.
 3. The flush valve according to claim 1, wherein therelief inlet of the relief system is in direct flow communication withthe control chamber.
 4. The flush valve according to claim 1, whereinthe mechanical relief device comprises a ball relief valve having a ballbiased by a spring toward a closed position of the relief inlet, andwherein the spring bias is adapted to be overcome based on the fluidpressure at the relief inlet exceeding the predetermined fluid pressureat the relief inlet.
 5. The flush valve according to claim 1, whereinthe mechanical relief device is a compressible plug constructed of amaterial which is adapted to be compressed based on the fluid pressureat the relief inlet exceeding the predetermined fluid pressure at therelief inlet.
 6. The flush valve according to claim 1, wherein the mainvalve element is a swing check valve.
 7. The flush valve according toclaim 1, wherein the relief valve is configured to open based on thefluid pressure at the relief valve exceeding a predetermined fluidpressure to cause fluid to vent from the fluid inlet to the fluid outletand relieving the pressure within the valve without causing opening ofthe main valve element.
 8. A diaphragm flush valve comprising a plasticvalve body including a fluid inlet and a fluid outlet and a main valveelement adapted for movement to allow fluid flow between the fluid inletand the fluid outlet based on a pressure differential across a portionof the main valve element, the valve including a vent system for ventingfluid from the fluid inlet to the fluid outlet to establish a pressuredifferential across a portion of the main valve element to open the mainvalve element, wherein the improvement comprises incorporating apressure relief system within the vent system of the valve comprising arelief valve in flow communication with the fluid inlet of the valve,the relief valve configured to open based on the fluid pressure at therelief valve exceeding a predetermined fluid pressure to cause fluid tovent from the fluid inlet to the fluid outlet and relieving the pressurewithin the valve, and incorporating a bleed fitting having a first endconnected to the valve and a second end connected to a solenoid suchthat a piston of the solenoid moves into and out of the bleed fitting,wherein the vent system comprises a control chamber in flowcommunication with the fluid inlet of the valve, a vent chamber in flowcommunication with the control chamber through a vent inlet passageextending between the control chamber and the vent chamber, and a ventoutlet passage extending between and in flow communication with thefluid outlet and the vent chamber, the pressure relief system furthercomprises a relief chamber having a relief inlet in flow communicationwith the control chamber and a relief outlet in flow communication withthe vent outlet, and wherein the relief valve extends within and ispositioned completely within the relief chamber, and at least the ventoutlet passage and the vent inlet passage the vent s stem are positionedwithin the bleed fitting and the vent outlet passage, the vent inletpassage, and the relief chamber are positioned parallel to each otherand the relief outlet is positioned perpendicularly to the reliefchamber and the vent outlet passage.
 9. The diaphragm flush valveaccording to claim 8, wherein the relief valve comprises a ball reliefvalve having a ball biased by a spring toward a closed position of therelief inlet, and wherein the spring bias is adapted to be overcomebased on the fluid pressure at the relief inlet exceeding thepredetermined fluid pressure.
 10. A method of relieving the internalpressure within a diaphragm valve assembly comprising: providing a valveincluding a fluid inlet, a fluid outlet and a main valve element adaptedfor movement to allow fluid flow between the fluid inlet and the fluidoutlet based on a pressure differential across a portion of the mainvalve element, the valve comprising a vent system for venting fluid fromthe fluid inlet to the fluid outlet to establish a pressure differentialacross a portion of the main valve element to cause the main valveelement to open, the vent system comprising a control chamber in flowcommunication with the fluid inlet of the valve, a vent chamber in flowcommunication with the control chamber through a vent inlet passageextending between the control chamber and the vent chamber, and a ventoutlet passage extending between and in flow communication with thefluid outlet and the vent chamber, incorporating a bleed fitting havinga first end connected to the valve and a second end connected to asolenoid such that a piston of the solenoid moves into and out of thebleed fitting, and incorporating a pressure relief system within thevent system and within the bleed fitting of the valve comprising arelief chamber having a relief inlet in flow communication with thefluid inlet of the valve and a relief outlet in flow communication withthe fluid outlet of the valve with the relief valve extending within therelief chamber and a mechanical relief valve positioned completelywithin the relief chamber and in flow communication with the fluid inletof the valve, whereby the relief valve is adapted to open based on thefluid pressure at the relief valve exceeding a predetermined fluidpressure, thereby cause fluid to vent from the fluid inlet to the fluidoutlet and relieving the pressure within the valve, wherein at least thevent outlet passage and the vent inlet passage of the vent system andthe relief system are positioned within the bleed fitting and the ventoutlet passage, the vent inlet passage, and the relief chamber arepositioned parallel to each other and the relief outlet is positionedperpendicularly to the relief chamber and the vent outlet passage. 11.The method of claim 10, wherein the relief valve comprises a ball reliefvalve having a ball biased by a spring toward a closed position of therelief inlet, and wherein the method further comprises: determining afluid pressure threshold for the valve body, and providing the springwith a bias which is adapted to be overcome based on the fluid pressureat the relief inlet exceeding the fluid pressure threshold.
 12. A flushvalve for a waste water system, comprising: a valve comprising a fluidinlet, a fluid outlet and a main valve element extending between thefluid inlet and the fluid outlet, the main valve element adapted formovement to allow fluid flow between the fluid inlet and the fluidoutlet based on a pressure differential across a portion of the mainvalve element; a vent system comprising a control chamber in flowcommunication with the fluid inlet of the valve and a vent outlet inflow communication with the fluid outlet of the valve; a solenoid havinga piston configured to open to establish flow communication between thecontrol chamber and the vent outlet thereby venting fluid from thecontrol chamber to the fluid outlet and establishing a pressuredifferential across a portion of the main valve element and permittingthe main valve element to open for fluid flow between the fluid inletand fluid outlet of the valve, and to close to prevent fluidcommunication between the control chamber and the vent outlet to closethe main valve element; a bleed fitting having a first end threadedlyconnected to the valve and a second end threadedly connected to thesolenoid such that the piston of the solenoid moves into and out of thebleed fitting; and a relief system incorporated into the bleed fittingcomprising a relief chamber having a relief inlet in flow communicationwith the control chamber, a relief outlet in flow communication with thevent outlet, and a mechanical relief device positioned entirely withinthe bleed fitting configured to open and close the relief inlet based ona predetermined fluid pressure at the relief inlet, thereby ventingfluid from the control chamber to the vent outlet, wherein the bleedfitting comprises at least a portion of the vent system and the reliefsystem positioned therein.